title: Cryogenic temperature measurement of THz meta-resonance in symmetric metamaterial superlattice.
abstract: A symmetric metamaterial superlattice is introduced accommodating a high Q-factor trapped mode. THz time-domain spectroscopy is employed to measure the transmission spectra, identifying the excitation of trapped and open-modes in the meta-resonances. A finite-difference-time- domain calculation showed that the trapped mode excitation is from the cancelation of current densities among the nearest-neighboring meta-particles. A cryogenic temperature THz measurement is carried out to examine the temperature dependence of resonance characteristics of meta-resonances. At low temperatures, the temperature-independent radiative damping is dominant for the open-mode, while the Q-factor of the trapped mode is determined by the temperature-dependent phonon scattering and temperature-independent defect scattering with the radiative damping significantly suppressed. When compared with the room temperature measurement, a 16% increase in Q-factor is observed for the trapped mode, while a 7% increase for the open-mode at the cryogenic temperature.
authors.affiliation: Department of Physics and Quantum Metamaterials Research Center, Ewha Womans University, Seoul, South Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Woo
authors.forename: E S
authors.initials: ES
authors.lastname: Kim
authors.forename: E
authors.initials: E
authors.lastname: Choi
authors.forename: Boyoung
authors.initials: B
authors.lastname: Kang
authors.forename: Hyun-Hee
authors.initials: HH
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: Y U
authors.initials: YU
authors.lastname: Lee
authors.forename: Tae Y
authors.initials: TY
authors.lastname: Hong
authors.forename: Jae H
authors.initials: JH
authors.lastname: Kim
authors.forename: J W
authors.initials: JW
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D003080:Cold Temperature; D008420:Manufactured Materials; D008422:Materials Testing / Q000379:methods*; D055068:Terahertz Spectroscopy / Q000379:methods*; D013817:Thermography / Q000379:methods*